Process fob the manufactobe of



PROCESS FOR THE MANUFACTURE OF VIT B1 No Drawing. Application December 15, 1937, Se-

rial No. 180,025. In Switzerland. July 22, 1937 11 Claims.

It has been found that 2-methyl-2-alkoxy-3- chloro-tetrahydrofuranes, easily obtainable by the reaction between an aliphatic primary alcohol and aceto-chloro-butyrolactone in the presence of sulphuric acid, can be condensed with 2 methyl-4-amino-5 thioformyl aminomethyl-pyrimidine to vitamin B1. The conversion of 2- methyll-amino-5 thioformyl aminomethyl-pyrimidine into vitamin B1 is actually known (Journal of the Chemical Society, London, 1937, page 367 using 1-acetoxy-3-chloropentanone(4) for the reaction. No indication is given regarding the yield obtained. A very poor yield wasobtained by following the directions given. Far better results are obtained by the present process.

Itcould not be anticipated that the chlorineatom of Z-methyl-2-a1koxy-3-ghloro-tetrahydrofuranes is sufliciently reactive for the reaction 20 with 2-methyl 4 amino 5 thioformylaminomethyl-pyrimidine to proceed under very mild conditions. It is still more surprising that the thiazole-ring is formed under these conditions when this is only possible after rupture of the furane-ring. v r

The reaction can be illustrated by the following formula:

heated for 20 hours at 45-50 C. After cooling the product is taken up in 100 parts by weight of 3n hydrochloric acid. The solution is (31311-1 fled by the filtration and concentrated in vacuo to 50-60 parts by weight at moderate temperature and the residue precipitated with 400 parts by weight of absolute alcohol, whereby the resulting vitamin B1 separates in crystals. The recrystallized product melts at 248-250" C. Yield parts by weight.

Example 2 11 parts by weight of calcium-bromide (with of water) are dissolved in 40 parts by weight of 80% acetic acid and 18.2 parts by weight of Z-methyl -4 amino- 5 -thioformylamino-methylpyrimidine added. After a short time the hydrobromide of the pyrimidine precipitates which causes the whole to solidify. 15 parts by weight of Z-methyl-2-methoxy-3-chloro-tetrahydrofurane are then added and stirred for 10 hours at 40? C. After this time, a nearly homogeneous solution is obtained, from which 18 parts by weight of vitamin B1 are isolated by working up in accordance with Example 1.

I claim:

1. Process for the manufacture of vitamin B1 which comprises reacting Z-methyI-Z-aHroXy-E- onion pl ce-om CH8 H2 N-GH no N-on o1 CHr-(J (Learns-0115+ spam-t iL HQN It is evident that other N-mono-substituted derivatives of thioamides can also be converted into 4-methyl-5-oxy-ethyl-thiazolium compounds in this manner; but of the further repre- 4 sentatives of this class of substances so far obtained none shows remarkable physiological effects.

For carrying out the reaction it is advantageous to employ a solvent. The. most suitable solvents are: water in the presence of an equivalent of mineral acid, highly concentrated acetic acid and highly concentrated formic acid. Condensing agents can also be used.

Example 1 chloro tetrahydrofurane with 2 methyl 4- amino-5-thioformylaminomethyl-pyrimidine.

2. Process for the manufacture of vitamin B1 which comprises reacting 2-methyl-2-alkoxy-3- chloro tetrahydrofurane with 2 methyl 4- amino-5-thioformylaminomethyl-pyrimidine in the presence of a solvent.

3. Process for the manufacture of vitamin B1 which comprises reacting 2-methyl-2-alkoxy-3- chloro tetrahydrofurane with 2 methyl 4- amino-5-thioformylaminomethyl-pyrimidine the presence of formic acid.

4. Process for the manufacture of vitamin B1 3 which comprises reacting 2-methyl-2-alkoxy-3- chloro tetrahydrofurane with 2 methyl 4- amino -5-thioformylaminomethy1-pyrimidine in the presence of acetic acid.

5. Processfor the manufacture of vitamin B1 which comprises reacting 2-methyl-2-alkoxy-3- chloro tetrahydrofurane with 2 methyl 4- hmino-fi-thioiormylaminomethyi-pyrimidine in the presence 0! I solvent and. cnlclum bromide.

6. Pmoeoo for the mnnui'ncture oi vitamin B1 which comprises reacting 2-methyl-2-methoxy-3- chloro tetrnhydroturcne with 2- methyl 4- v nmino-fi-thioiormyluninomethyl-pyrimidine.

7. Process for the mnnuincture of vitamin B1 which comprises reacting 2-methyiP2-ethoxy-3- chloro tetruhydroi'urnne with 2 methyl 4- nmino-fi-thiotormylnminomethyl-pyrimidine.

8. Process for the manufacture oi vitamin 31 which comprises reacting 2-methyi-2-methoxy-3- chioro tetmhydrofurane with 2 methyl 4- nmino-li-thioiormylaminomethyl-pyrimidine in 15 thepreeeneeoii'ormicacid.

9. Process tor the manufacture oi vitamin 131 nminoJ-thioiormylnminomethyl-pyrimidine in the presence of formic acid.

10. Proceu tor the manufacture oi vitamin B1 which comprises reacting 2-methyi-2-methoxy-3- chloro tetrohydroiurane with 2 methyl 4- nmino-li-thioiormylaminomethyi-pyrimidine in the presence oi formic acid and calcium bromide.

11. Process for the manufacture of vitamin B1 which comprises reacting 2-methyl-2-eth0xy-3- chloro tetrahydroiurane with 2 methyl 4- amino-S-thioIOrmyIaminOmethyI-pyrimidine in the presence of formic acid and calcium bromide.

' MAX KIJNGENFUSS. 

